JP2576735B2 - Clamping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamp device, and more particularly to a clamp device for gripping a load having an engaging portion formed on the outer periphery.

[0002]

2. Description of the Related Art Conventionally, there is a clamp device as an attachment mounted on, for example, an unmanned forklift. This clamp device transports a load by clamping a cylindrical or cylindrical load such as roll paper by a pair of clamp arms. At this time, the controller causes the opening and closing mechanism to close the pair of clamp arms.

[0003] When the controller detects that a load is nipped by the pair of clamp arms based on a load detection sensor provided on the pair of clamp arms, the controller causes the opening and closing mechanism to close the pair of clamp arms. Stop. Thereafter, the controller supplies hydraulic oil to the lift cylinder from the hydraulic pump, and raises the clamp device. At this time, the pressure sensor detects the weight of the load including the clamp device.

[0004] When the load held by the unmanned forklift is placed in a predetermined place, the controller lowers the clamp device. Then, when a load is placed, the load applied to the cylinder decreases, and the output voltage of the pressure sensor changes. Based on this change, the controller determines that the loading has been completed and stops lowering the clamp device. After that, the controller opens the pair of clamp arms by the opening / closing mechanism to release the load.

[0005]

SUMMARY OF THE INVENTION The present applicant has devised an unmanned transport system in which sand, a solvent and the like are put in a relatively small container and the container is transported. However, there is a risk that the container may be deformed or damaged, and it is difficult to use the conventional Kunlamp apparatus as it is.

In the case of a heavy load such as roll paper, the completion of grounding (loading) of the load held by the clamp device is reliably detected by a pressure sensor. However, when the load to be conveyed is light, there is a problem that the weight change including the weight of the clamp device is small even if the load is placed, so that the pressure sensor cannot accurately detect the change in weight.

The present invention has been made to solve the above problems, and a first object of the present invention is to hold a load in a vertical state without strongly holding the load for preventing deformation and damage of the load. It is to provide a clamping device.

A second object is to provide a clamp device that can reliably detect the completion of placing a light load. Third
It is an object of the present invention to provide a clamp device that can prevent a malfunction of a detection sensor that detects completion of placing a light load.

A fourth object is to hold the load without causing deformation or damage of the load when transporting the bottomed cylindrical container, and to make sure that the loading is completed even after the reversing operation of the load. To provide a clamp device capable of detecting the pressure.

[0010]

According to a first aspect of the present invention, there is provided a closed position capable of engaging with an engaging portion provided on an outer periphery of a load by opening and closing operation. And a pair of clamp arms arranged at an unengageable open position, abutting against the lower surface of the engaging portion and supporting the load in a loosely fitted state, and opening and closing drive means for opening and closing the pair of clamp arms. And a lifting means for raising and lowering the pair of clamp arms.

In order to achieve the second object, the invention according to a second aspect is directed to a mechanism for detecting that at least one of the pair of clamp arms has been engaged with an engagement portion of a load. The gist is that the combination detection means is provided.

According to a third aspect of the present invention, in order to achieve a third object, one clamp arm has a movable portion having a contact portion protruding from a contact surface contacting a lower surface of the engagement portion. The gist is that the movable member is provided with a detection member of engagement detection means at a position off the extension of the movement trajectory of the abutment portion. And

In order to achieve the fourth object, the invention according to a fourth aspect relates to a closed position capable of engaging with a pair of upper and lower engaging portions provided for a bottomed cylindrical load. A pair of clamp arms which are arranged at an unfittable open position, abut against one of the engagement portions and support the load in a loosely fitted state, opening and closing drive means for opening and closing the pair of clamp arms, and Lifting means for raising and lowering the pair of clamp arms, rotation driving means for rotating the pair of clamp arms, and upper and lower contact surfaces of the clamp arms engaged with the pair of upper and lower engaging portions are provided respectively. Engagement detecting means for detecting that the clamp arm has been engaged with a load engaging portion; rotating state detecting means for detecting a rotating state of the pair of clamp arms; and rotating state detecting means. A pair of clampers based on the Determination means for determining the rotation state of the arm, and activation control means for validating one of the engagement detection means provided on the clamp arm based on a detection signal of the determination means. This is the gist.

[0014]

The load is loosely fitted by closing the pair of clamp arms by the opening / closing drive means. Thereafter, when the pair of clamps is raised by the lifting / lowering means, the engagement portion of the load is engaged with the pair of clamp arms, and the load is loosely supported by the pair of clamp arms. That is, the load is gripped by the pair of clamp arms in an unclamped state,
A fragile load is grasped without being damaged.

[0015] The engagement detecting means provided on at least one of the pair of clamp arms detects whether the engagement portion of the load and the pair of kunlap arms are in the engaged state. Then, when it is detected that the vehicle is not in the engaged state based on the detection signal of the engagement detecting means at the time of loading, it is determined that the loading is completed, and even a light load is reliably detected.

Further, since the detected member of the engagement detecting means is provided at a position off the extension of the movement locus of the contact portion of the movable member, the movable member can be prevented from being affected by the load.

The load is loosely fitted by the pair of clamp arms based on the opening / closing operation of the opening / closing drive means, and the pair of clamp arms is raised by the lifting / lowering means. Engage. Then, the load is used in a loosely fitted state by the pair of clamp arms. The engagement between the engaging portion and the clamp arm is detected by the engagement detecting means. The turning state detecting means detects a turning state of the pair of clamp arms turned by the turning drive means. The determining means determines the rotating state of the pair of clamp arms based on the detection signal of the rotating state detecting means. The activation control unit activates one of the engagement detection units provided on the upper and lower contact surfaces of the clamp arm based on the detection signal of the determination unit. Therefore, while the load is freely rotated,
The erroneous determination of the engagement of the load is prevented by the detection signal from the invalidated engagement detection means.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in an unmanned forklift will be described below with reference to FIGS.

The unmanned forklift 1 shown in FIG. 1 performs a cargo handling operation based on a work program stored in advance.
In the present embodiment, the solvent and the like supplied into the container C as a load are discharged by rotating the container C at a predetermined location. The container C has a bottomed cylindrical shape,
Engagement pieces F1 and F2 as engagement portions are formed on the upper and lower outer peripheral surfaces, respectively.

As shown in FIGS. 1 to 3, the unmanned forklift 1 has a pair of legs 2 projecting forward from the front thereof in the horizontal direction. Has been established. A clamp device 5 is supported on the mast 3 via a clamp bracket 4. The clamp device 5 moves up and down together with the clamp bracket 4 by winding a chain (not shown) in accordance with expansion and contraction of a lift cylinder 6 as a lifting / lowering means extending in parallel with the mast 3.

A circular support bracket 7 constituting the clamp device 5 is supported and fixed to the clamp bracket 4. On the front surface of the support bracket 7, a gear 8 having an annular shape slightly smaller in diameter than the support bracket 7 and having a gear formed on its inner peripheral surface is rotatably provided. In addition, a rotary drive mechanism 11 as a rotary drive unit including an oil pump 9 and a gear mechanism 10 is provided on the upper rear surface of the support bracket 7.

The gear mechanism 10 of the rotary drive mechanism 11 is meshed with the gear 8, and the gear mechanism 10 is driven by the operation of the oil pump 9, so that the gear 8 rotates. A circular support plate 1 having the same diameter is provided on the front surface of the gear 8.
2 is fixed and rotates integrally with the gear 8.

Also, as shown in FIGS.
A connection support plate 13 is fixed to a lower part of the front surface of the second member 2. A pair of regulation support plates 14 are fixed to both sides in the front width direction of the connection support plate 13 so as to face each other. The regulating support plate 14 is provided with regulating bolts 15 from inside thereof.
Is screwed. A lock nut 16 is screwed into a male screw portion of a regulating bolt 15 projecting outward from the regulating support plate 14, and the regulating bolt 15 is positioned.

An outwardly bent support piece 17 is fixed to the front side surface of the regulation support plate 14, and an open / close detection sensor 18 for detecting the open / close state of clamp arms 21, 22 described later is attached to the support piece 17. (Proximity sensor in this embodiment) is mounted.

A pair of holding plates 19 are fixed to the upper and lower sides of the connecting support plate 13 so as to face the pair of holding plates 19 so as to sandwich the pair of regulating support plates 14 in a state of extending in the horizontal direction. A pair of left and right rotation shafts 20 are supported at the front portions of the pair of holding plates 19 so as to be rotatable in a state orthogonal to the holding plates 19. A pair of clamp arms 21 and 2 facing each other
2 is supported by the rotation shaft 20 so as to be integrally rotatable near its base end. A pair of clamp arms 21 and 22
Are flanges 21a, 21b, 22a, 2
2b is formed so as to extend orthogonally to the outside and has a U-shaped cross section.

The pair of clamp arms 21 and 22 are rotatable integrally with the support plate 12 by the driving of the rotation drive mechanism 11.
When the rotary drive mechanism 11 rotates the pair of clamp arms 21 from the normal horizontal state, the pair of clamp arms 21 and 22 rotate counterclockwise in FIG. When the pair of clamp arms 21 and 22 are rotated from the inverted state where they are rotated by 180 °, the pair of clamp arms 21 and 22 are rotated clockwise by the rotation driving mechanism 11.

Curved portions 23 and 24 are formed at the distal ends of the pair of clamp arms 21 and 22 so as to bend outward, respectively. A grip portion 25 is formed by the curved portions 23 and 24. Also, flanges 21a, 2 of a pair of clamp arms 21, 22 are provided on upper and lower ends of the curved portions 23, 24, respectively.
Contact portions 26a, 26 provided continuously with 1b, 22a, 22b
b, 27a and 27b are formed to project outward.

The contact portions 26a, 26b of one curved portion 23
Is formed so as to be larger than the width of the engagement pieces F1 and F2 of the container C, and the contact portions 27a and 27b of the other curved portion 24 are formed so as to be smaller than the width of the engagement pieces F1 and F2. .

Then, the container C is supported by the grip portion 25 in a loosely fitted state in which the container C can be relatively moved in the vertical direction. The pair of clamp arms 21 and 22
The flanges 21a, 21b, 2 on the rear surface of the base end
Drive connecting plates 29 and 30 are fixed between 2a and 22b, respectively. A pair of upper and lower drive connection pieces 31 are fixed to the rear surfaces of the drive connection plates 29 and 30 in a horizontal state. A hydraulic opening / closing cylinder 32 as an opening / closing drive unit is disposed between the drive connection pieces 31, and a support rod 33 and a piston rod 34 are connected to the drive connection piece 31 via connection pins 35, respectively.

The piston rod 34 is connected to a piston (not shown) in the hydraulic opening / closing cylinder 32, and the support rod 33 is fixed to the main body of the hydraulic opening / closing cylinder 32.
Therefore, the piston (not shown) in the hydraulic opening / closing cylinder 32 operates to extend and retract the hydraulic opening / closing cylinder 32, thereby causing the support rod 33 and the piston rod 34, the connecting pin 35, the drive connecting piece 31, and the drive connecting plates 29, 30 to move. The pair of clamp arms 21 and 22 are configured to rotate around the rotation shaft 20 through the intermediary of the clamp arms 21 and 22.

Then, a pair of clamp arms 21 and 22
Is arranged at the closed position when the hydraulic open / close cylinder 32 is in the extended state, and is arranged at the open position when the hydraulic open / close cylinder 32 is in the contracted state.

That is, when the hydraulic opening / closing cylinder 32 is extended, the pair of clamp arms 21 and 22 rotate via the support rod 33 and the piston rod 34, the connection pin 35, the drive connection piece 31 and the drive connection plates 29 and 30. It rotates around the shaft 20. Therefore, the pair of clamp arms 21 and
2 performs the closing operation to bring the curved portions 23 and 24 of the grip portion 25 closer to each other.

When the hydraulic opening / closing cylinder 32 contracts,
Support rod 33, piston rod 34, connecting pin 3
5. The pair of clamp arms 21 and 22 rotate about the rotation shaft 20 via the drive connection piece 31 and the drive connection plates 29 and 30. Therefore, the pair of clamp arms 21 and 22 perform the opening operation, and separate the curved portions 23 and 24 of the grip 25 from each other.

Contact plates 36 are fixed to the outer side portions of the pair of drive connection pieces 31, respectively. This contact plate 3
Numerals 6 abut against the regulating bolts 15 when the hydraulic opening / closing cylinder 32 is extended. Therefore, the closing operation of the pair of clamp arms 21 and 22 due to the extension of the hydraulic opening / closing cylinder 32 is restricted, that is, the approach of the curved portions 23 and 24 of the pair of clamp arms 21 and 22 is restricted.

Flanges 21a, 21b, 22a, 22 at the base end sides of the pair of clamp arms 21, 22
Auxiliary brackets 37 are provided between the respective b. A bent detection member 38 is fixed to the lower outer surface of the auxiliary bracket 37. When the pair of clamp arms 21 and 22 are opened by contraction of the hydraulic opening / closing cylinder 32, the detected member 3
Reference numeral 8 does not face the opening / closing detection sensor 18 and turns off the opening / closing detection sensor 18. Conversely, the pair of clamp arms 2 due to the extension of the hydraulic opening / closing cylinder 32
When the contact plate 36 abuts on the regulating bolt 15 by performing the closing operations 1 and 22, the detected member 38 is opposed to the open / close detection sensor 18 so that the open / close detection sensor 18 is turned on. Has become.

As shown in FIGS. 2, 3 and 6, elongated holes 39 extending in the longitudinal direction are provided in the center of the pair of holding plates 19 in the width direction. A sliding shaft 40 is provided between the pair of holding plates 19 so as to pass through the long hole 39 in parallel with the rotating shaft 20. Large-diameter portions 41 are formed at both ends of the sliding shaft 40, and the large-diameter portions 41 are slidably disposed along the long holes 39. A flange 42 is provided on the upper end of the large-diameter portion 41 provided on the upper portion of the sliding shaft 40.
The flange 42 is engaged with the outer peripheral edge of the elongated hole 39 so that the sliding shaft 40 is held between the pair of holding plates 19.

The sliding shaft 4 between the pair of large diameter portions 41
A pair of collars 43 and 44 are rotatably attached to the zero. The pair of collars 43 and 44 have connecting rods 45 and 4 respectively.
The connecting rods 45 and 46 are projected outward through insertion holes 47 provided in the side surfaces of the pair of clamp arms 21 and 22 as shown in FIGS.

As shown in FIG. 1 to FIG.
Between the flanges 21a, 21b, 22a, 22b of the pair of clamp arms 21, 22 in front of the
8, 49 are rotatably inserted and supported. The connecting rod 46 is fixed to the insertion shaft 48, and the connecting rod 45 is fixed to the insertion shaft 49. Therefore, the pair of clamp arms 2 are moved by the contraction operation of the opening / closing hydraulic cylinder 32.
When the first and second members perform the opening operation, the sliding shaft 4 is inserted through the insertion shafts 48 and 49, the connecting rods 45 and 46, and the collars 43 and 44.
0 slides forward along the elongated hole 39, and the large diameter portion 41 of the sliding shaft 40 abuts on the front end of the elongated hole 39, thereby restricting the sliding of the sliding shaft 40. For this reason, a pair of clamp arms 2
The opening operations of the first and second units are regulated, and the respective speeds are set to be the same.

When the pair of clamp arms 21 and 22 perform the closing operation by the extension operation of the opening / closing hydraulic cylinder 32, they slide through the insertion shafts 48 and 49, the connecting rods 45 and 46, and the collars 43 and 44. The shaft 40 slides rearward along the elongated hole 39, and the large diameter portion 41 of the sliding shaft 40 abuts on the rear end of the elongated hole 39, thereby restricting the sliding of the sliding shaft 40.

The pair of clamp arms 21 and 22
Performs the closing operation, the sliding shaft 40 slides backward along the elongated hole 39, and the large diameter portion 41 of the sliding shaft 40
Prior to contacting the rear end portion 9, the contact plate 36 contacts the regulating bolt 15, and the detected member 38 faces the open / close detection sensor 18.

That is, the pair of clamp arms 21 and
The regulation of the closing operation 2 is performed by the contact between the regulation bolt 15 and the contact plate 36, but the regulation by the long hole 39 is performed as a safety device when the position of the regulation bolt 15 is inappropriate. .

As shown in FIGS. 7 and 9, the contact portions 26a and 26b of the clamp arm 21 with which the engagement pieces F1 and F2 of the container C abut are respectively provided with a pair of through holes 50a and 50b.
Are formed. Curved portion 2 of the clamp arm 21
A pair of upper and lower load detecting mechanisms 51a and 51b as engagement detecting means are provided between the outer contact portions 26a and 26b in FIG.
A set is provided.

The load detecting mechanisms 51a and 51b will be described. As shown in FIGS.
An auxiliary plate 52 extending in the vertical direction is fixed to the outside of the curved portion 23 between a and 26b, and both ends are bent at upper and lower side surfaces of the auxiliary plate 52, and mounting portions 53a, 53b and 54 are provided.
a, 54b provided with sensor mounting brackets 53, 5
4 are attached by bolts 55. And
Load detecting sensors 56a, 56b are mounted on the mounting portions 53a, 53b, 54a, 54b so as to face the respective through holes 50a, 50b.

Support members 57a, 57b are provided outside the curved portion 23 between the auxiliary plate 52 and the through holes 50a, 50b.
Is fixed, and the support pins 57 are attached to the support members 57a and 57b.
8a and 58b are fixed. The support pins 58a,
Rotating levers 59a and 59b as movable members are provided at 58b.
Are rotatably provided, and the rotating levers 59a and 59b are prevented from coming off by a nut 60.

The rotating levers 59a, 59b are provided with bent portions 61a, 61b formed in a crank shape on the load detection sensors 56a, 56b side from the support pins 58a, 58b. Detected portions 62a and 62b as detection members are bent at one ends of the rotating levers 59a and 59b corresponding to the load detection sensors 56a and 56b so as to face the load detection sensors 56a and 56b. ing.

The rotation levers 59a, 59 corresponding to the support pins 58a, 58b and the through holes 50a, 50b, respectively.
At the other end of 9b, bifurcated support portions 63a and 63b are formed by bending, and support pins 64a and 63b are provided on the support portions 63a and 63b.
The contact members 65a and 65b as contact portions are formed by 64b.
Are provided so as to be swingable. The contact members 65a, 6
5b is inserted into the through holes 50a, 50b via guide cylinders 66a, 66b fixed to the through holes 50a, 50b.

Further, regulating plates 69a, 69b are fixed to the curved portion 23 between the rotating levers 59a, 59b, and regulating bolts 70a, 69b are fixed to the regulating plates 69a, 69b.
70b is screwed. Lock nuts 71a and 71b are screwed into male screws of the restriction bolts 70a and 70b projecting from the restriction plates 69a and 69b.
Positioning of 0a and 70b is performed. The restricting bolts 70a, 70b are connected to the rotating levers 59a, 59b.
The bent portions 61a and 61b of FIG.

The rotation levers 59a, 59b between the bent portions 61a, 61b and the detected portions 62a, 62b.
b are fixed to the side surfaces thereof, and a coil spring 68 is provided between the locking members 67a and 67b.
Is locked. Then, due to the urging force of the coil spring 68, the load detecting portions 62a, 62b of the rotating levers 59a, 59b approach each other, and the bent portion 61
a, 61b contact the regulating bolts 70a, 70b.

At this time, the detected parts 62a and 62b of the rotating levers 59a and 59b do not face the load detection sensors 56a and 56b, and the load detection sensors 56a and 56b are turned off. On the other hand, the urging force of the coil spring 68 causes the support portions 63 of the rotating levers 59a, 59b to be supported.
The contact members 65a and 65b provided on the a and 63b project from the contact portions 26a and 26b through the guide cylinders 66a and 66b and the through holes 50a and 50b.

As shown in FIG. 9, the engaging piece F1 of the container C is engaged with the abutting portion 26a of the clamp arm 21, and the engaging piece F1 is pressed against the urging force of the coil spring 68. When the member 65a is pressed, the turning lever 59a turns around the support pin 58a in a direction in which the bent portion 61a is separated from the regulating bolt 70a. At this time,
The detected portion 62a of the rotating lever 59a is connected to the load detection sensor 56.
a, and turns on the load detection sensor 56a.

The contact portion 26 of the clamp arm 21
When the engagement piece F2 of the container C engages with the b, the engagement piece F2 presses the contact member 65b. As a result, the detected part 62b of the rotating lever 59b faces the load detection sensor 56b in the same manner as described above, and the load detection sensor 56b is turned on.

As shown in FIG. 5, a bent first dog 72 is provided on the outer peripheral surface of the support plate 12 through which a reference line H centered at the center point O passes. Has a detection surface 72a extending forward. A second dog 73 is provided on the outer peripheral surface of the support plate 12 at a position rotated by an angle θ1 in the counterclockwise direction from the reference line H, and the front end of the dog 73 has a detection surface 7 extending forward.
3a are formed. The extended lengths of the detection surfaces 72a, 73a of the dogs 72, 73 are the same.

Further, the angle θ from the reference line H in the counterclockwise direction
A bent intermediate dog 74 is provided on the outer peripheral surface of the support plate 12 at the position rotated twice, and a detection surface 74a extending forward is formed at the tip of the intermediate dog 74. The detection surface 74a of the intermediate dog 74 is the first
The dogs 72, 73 are formed to be slightly longer than the detection surfaces 72a, 73a.

As shown in FIGS. 4 and 5, the mounting bracket 7 is provided on the outer peripheral surface of the support bracket 7 through which the reference line H passes.
The mounting bracket 75 is provided with a reference state sensor 76 as state detecting means so as to face the detection surface 72a of the first dog 72. The reference state sensor 76 includes a deceleration sensor 76a and a stop sensor 76b.
It is composed of A mounting bracket 77 is provided on the outer peripheral surface of the support bracket 7 at a position rotated clockwise by an angle θ3 from the reference line H, and the mounting bracket 77 faces the detection surface 74 a of the intermediate dog 74. , An intermediate position detection sensor 78 is mounted.

A mounting bracket 79 is provided on the outer peripheral surface of the support bracket 7 at a position rotated by an angle θ4 clockwise from the reference line H, and the mounting bracket 79 is provided on the detection surface 73 a of the second dog 73. A reversal state sensor 80 as a state detection means is mounted so as to be opposed to. The reversing state sensor 80 includes a deceleration sensor 80a and a stop sensor 80b.

Therefore, the pair of clamp arms 21 and 22
Is in a reference state, that is, in a horizontal state in which the pair of clamp arms 21 and 22 are positioned on the upper side, the detection surface 72a of the first dog 72 and the reference state sensor 76 face each other, and the reference state sensor 76 It is turned on. From this state, when the support plate 12 is rotated in the counterclockwise direction by the rotation drive mechanism 11, the detected surface 74a of the intermediate dog 74 and the intermediate position detection sensor 78 face each other, and the intermediate position detection sensor 78 is turned on. It has become. At this time,
The pair of clamp arms 21 and 22 are turned about 135 ° counterclockwise from the reference state.

The intermediate dog 74 passes through the reversing state sensor 80 before reaching the intermediate position sensor 78.
Since the length of extension of the detection surface 74a of the
The inversion state sensor 80 does not perform the ON operation.

Then, the support plate 1 is rotated by the rotary drive mechanism 11.
When the second dog 2 is further rotated in the counterclockwise direction, the detection surface 73a of the second dog 73 faces the inversion state sensor 80b, and the inversion state sensor 80 is turned on. At this time, the deceleration sensor 80a is turned on, and the rotation speed of the rotation drive mechanism 11 is reduced based on the on operation. Next, the detection surface 73a of the second dog is set to the stop sensor 80.
, And the rotary drive mechanism 11 is stopped based on the ON operation. At this time, the pair of clamp arms 21 and 22 are rotated about 180 ° counterclockwise from the reference state.
The rotating state is reversed.

A pair of inverted clamp arms 21 and 2
When the reference numeral 2 is returned to the reference state, the support plate 12 is rotated clockwise by the rotation drive mechanism 11 in the opposite direction. When the detection surface 72a of the first dog 72 faces the deceleration sensor 76a of the reference state sensor 76, the deceleration sensor 76a is turned on, and the rotation speed of the rotation drive mechanism 11 is reduced based on the on operation. You. Next, the stop sensor 76b opposes the detection surface 72a of the first dog 72 and turns on. Based on the on operation, the rotation drive mechanism 11 is stopped. As a result, the pair of clamp arms 2
1 and 22 return to the reference state.

Next, the electrical configuration of the unmanned forklift 1 configured as described above will be described. As shown in FIG. 10, a controller 81 serving as a rotation state detecting unit, a determining unit, and an activation control unit is provided with a memory 8 including a ROM and a RAM in which a work program and an arithmetic program are stored.
3 and a CPU. Controller 81
Is connected to the open / close detection sensor 18. The controller 81 determines the open / closed state of the pair of clamp arms 21 and 22 based on the detection signal from the open / close detection sensor 18,
The drive control of the hydraulic opening / closing cylinder 32 is performed.

A height sensor 82 is provided to the controller 81.
Is connected. The controller 81 is the lift sensor 8
2, the lift height of the clamp arms 21 and 22 is detected to control the lift cylinder 6.

The controller 81 is connected to load detecting sensors 56a and 56b.
a, 56b, the container C is located on either side of the contact portions 26a, 26b of the pair of clamp arms 21, 22.
It is configured to detect whether the engagement pieces F1 and F2 are engaged with each other and the container C is held in a loosely fitted state.

The reference state sensor 76, the inversion state sensor 80, and the intermediate position detection sensor 78 are connected to a controller 81, and the controller 81 includes the sensors 76, 78,
The drive control of the oil pump 9 is performed based on the detection signal of 80, and the rotation of the pair of clamp arms 21 and 22 is controlled. Further, the controller 81 determines the state of the pair of clamp lamp arms 21 and 22 based on the detection signals of the reference state sensor 76 and the inverted state sensor 80, and adjusts the load detection sensors 56a and 56 in accordance with the state.
b, only one of them is enabled, and the load is detected based on the detection signals of the enabled load detection sensors 56a and 56b.

The memory 83 stores in advance various kinds of work data such as unloading, loading work data, transport work data, travel data of the container C, and work of rotating the container C to discharge the solvent. ing.

Next, the operation of the unmanned forklift 1 having the clamp device constructed as described above will be described with reference to FIGS.
This will be described based on the flowchart shown in FIG. First, the outline of the procedure for transporting the container C by the unmanned forklift 1 will be briefly described. The unmanned forklift 1 travels to a reversing place for completely discharging the solvent remaining in the container C, and the container in the reversing state. After taking C, the container C is transported to a supply location where the solvent is supplied. Then, after the container C to which the solvent is supplied is transported to the discharge place, the container C is rotated to discharge the solvent. Thereafter, the container C is transported again to the reversing place and placed in an inverted state, and another container C in the inverted state is removed again and the same operation as described above is repeated.

The unmanned forklift 1 travels along a guide line (not shown) on the travel route based on the controller 81, and travels to a reversing place where the container C is placed in a reversing state. Then, the controller 81 stops just before the reversing location, and the controller 81 starts the loading operation of the container C in the inverted state based on the unloading operation data stored in the memory 83.

As shown in FIGS. 11 to 13, the controller 81 determines whether or not the pair of clamp arms 21 and 22 are in the inverted state based on the ON operation of the inverted state sensor 80 (STEP 100; S). Then, when the detection surface 73a of the second dog 73 faces the inverted state sensor 80 and the inverted state sensor 80 is turned on, the controller 81 validates only the detection signal of the load detection sensor 56b (S101).

When the controller 81 determines that the pair of clamp arms 21 and 22 are not in the inverted state based on the OFF operation of the inverted state sensor 80, the controller 81
Rotates the pair of clamp arms 21 and 22 via the gear 8 and the support plate 12 by driving the rotation drive mechanism 11 (S102). Then, the detection surface 73a of the second dog 73
Faces the inversion state sensor 80, and the inversion state sensor 80
Is turned on, the controller 81 operates the rotation drive mechanism 1
1 is stopped, and the process proceeds to STEP101.

Next, the controller 81 controls the pair of clamp arms 21 and 22 based on the pair of open / close detection sensors 18.
It is determined whether or not is open (S103). When the detected member 38 does not face the open / close detection sensor 18 and the open / close detection sensor 18 is off, the controller 8 determines that the pair of clamp arms 21 and 22 are open.
1 judges.

When the detected members 38 of the pair of clamp arms 21 and 22 face the open / close detection sensor 18 and the open / close detection sensor 18 is turned on, the pair of clamp arms 21 and 22 are closed. The controller 81 determines that there is, and the controller 81 contracts the hydraulic opening / closing cylinder 32 (S104). The pair of clamp arms 21 and 22 rotate around the rotation shaft 20 by the expansion and contraction operation of the hydraulic opening / closing cylinder 32. At this time, the connecting rods 45 and 46 fixed to the insertion shaft 49 cause the sliding rod 40 to slide along the elongated holes 39 while rotating the collars 43 and 44, and
1 is in contact with the distal end of the long hole 39 and a pair of clamp arms 2
The opening operations of the first and second opening operations are regulated. Then, the controller 81 stops the contraction operation of the hydraulic opening / closing cylinder 32 by restricting the contraction operation of the hydraulic cylinder 32 by restricting the opening operation of the pair of clamp arms 21 and 22. As a result, the opening operation of the pair of clamp arms 21 and 22 is completed.

Then, the pair of clamp arms 21,
After the controller 22 is opened, the controller 81
Is moved forward by a predetermined distance based on the traveling data stored in the pair of clamp arms 21 and 22.
The container C is positioned at No. 5 (S105). Thereafter, the controller 81 extends the hydraulic opening / closing cylinder 32 to close the pair of clamp arms 21 and 22. (S10
6).

Then, the pair of clamp arms 21,
It is determined based on the closing operation of 22 whether the detected member 38 has turned on in opposition to the open / close detection sensor 18 (S1).
07). When the detected member 38 is turned on facing the open / close detection sensor 18, the controller 81 stops the extension operation of the hydraulic open / close cylinder 32 (S108). As a result, the pair of clamp arms 21 and 22 are arranged at the closed position, and the gripper 25 is in a state where the container C is loosely fitted.

Next, the controller 81 controls the lift cylinder 6
To raise the pair of clamp arms 21 and 22. For this reason, the container C has a pair of clamp arms 21 and
Lifted by two. The controller 81 further determines whether or not the container C has been raised by a predetermined amount predetermined by the pair of clamp arms 21 and 22 based on the detection signal of the lifting sensor 82 (S111). When it is determined that the pair of clamp arms 21 and 22 have risen by a predetermined amount based on the detection signal from the lift sensor 82, the operation of the lift cylinder 6 is stopped (S11).
2). As a result, the container C has a pair of clamp arms 21,
It is supported in a loosely fitted state on the holding portion 25 of the carriage 22 and can be transported.

The controller 81 is connected to the load detecting sensor 5
It is determined whether or not 6b is turned on (S110). If it is not turned on, it is judged as abnormal and the operation is stopped. When the abutting portions 26b and 27b abut on the engaging piece F2 of the container C by raising the pair of clamp arms 21 and 22, the pair of abutting members 65b are pressed by the engaging piece F2 and the respective through holes 50b are formed. Immerse in (down). Then, the pair of rotation levers 59b are moved to the respective coil springs 6.
8 rotates about the support pin 58b against the urging force of No. 8.
Then, since the detected portion 62b of the rotating lever 59b faces the pair of load detection sensors 56b, the load detection sensor 56b is turned on.

[0075]

Thereafter, the controller 81 drives the rotary drive mechanism 11 to return the container C gripped in the inverted state (downward) to the reference state (upward), and drives the gear 8 and the support plate 12.
To rotate the pair of clamp arms 21 and 22 clockwise (S113). And the controller 81
Indicates that the detected surface 72a of the first dog 72 is the reference state sensor 76
It is determined whether or not the reference state sensor 76 is turned on to return the pair of clamp arms 21 and 22 to the reference state (S114). The detection surface 7 of the first dog 72
When 2a is turned on facing the reference state sensor 76,
The controller 81 stops driving the rotation drive mechanism 11 (S115). At this time, the container C is rotated 180 ° and upwardly held by the holding portions 25 of the pair of clamp arms 21 and 22 in a loosely fitted state. In addition, the engagement piece F1 of the container C is rotated by 180 ° so that the pair of clamp arms 21 and
2 and engages with the contact portions 26a and 27a.

The controller 81 validates only the detection signal of the load detection sensor 56a of the load detection mechanism 51a based on the fact that the pair of clamp arms 21 and 22 are in the reference state (S116). Thereafter, the controller 81 determines whether or not the detected portion 62a has been turned on while facing the load detection sensor 56a (S117).

The contact member 65a is pressed against the urging force of the coil spring 68 and enters the through hole 50a based on the engagement of the engaging piece F1 of the container C with the contact portion 26a. Then, the rotation lever 59a is moved to the support pin 58a.
Around the center. Therefore, the detected portion 62a faces the load detection sensor 56a, and the load detection sensor 56a turns on. By this ON operation, the controller 81
Determines that the container C has been normally taken and ends the unloading operation.

If the contact member 65a is not pressed due to the engagement of the engagement piece F1 of the container C with the contact portion 26a and the load detection sensor 56a does not operate, the controller 81 determines that there is an abnormality. Stop work.

Next, the unmanned forklift 1 supporting the container C in the loosely fitted state travels along the guide line under the control of the controller 81 based on the transfer data in the memory 83, and
The container C is transported to the supply location for supplying the solvent, and stopped. After the solvent is supplied into the container C at the supply location, the unmanned forklift 1 moves the container C to the discharge location where the solvent is discharged.
And stop. If the load detection sensor 56a is turned off during the operation of the unmanned forklift 1, the controller 81 determines that the container C has fallen from the pair of clamp arms 21 and 22 or is not normally supported in a loosely fitted state. Stop running and stop work.

When the unmanned forklift 1 stops at the solvent discharging place, the controller 81 starts the solvent discharging operation. As shown in FIGS. 14 and 15, the controller 81 determines whether or not the load detection sensor 56a is on based on a detection signal from the load detection sensor 56a (S
200), when the container C is off, it is determined that the container C is not normally supported in the loosely fitted state by the gripping portions 25 of the pair of clamp arms 21 and 22, and the discharge operation of the solvent is stopped as abnormal. .

When the load detection sensor 56a is on, the controller 81 rotates the gear 8 by the rotation drive mechanism 11 to rotate the support plate 12 and the pair of clamp arms 21 and 22 counterclockwise. (S20
1). Then, the container C held by the holding portions 25 of the pair of clamp arms 21 and 22 rotates, and the solvent in the container C is gradually discharged. The rotation of the support plate 12 causes the intermediate dog 74 provided on the outer peripheral surface of the support plate 12 to rotate.
Rotates counterclockwise. The controller 81 determines whether or not the detected surface 74a of the intermediate dog 74 has been turned on in opposition to the intermediate position detection sensor 78 (S202).
Stops the drive of the rotary drive mechanism 11. At this time, the container C gripped by the gripping portions 25 of the pair of clamp arms 21 and 22 stops at a position rotated by about 135 °. Then, the controller 81 holds this state for a predetermined time based on the work data stored in the memory 83, and
The solvent inside is discharged (S203).

After a lapse of a predetermined time, the controller 81 rotates the driving mechanism 11 based on the work data in the memory 83 to return the pair of clamp arms 21 and 22 to the reference state.
, The gear 8 is rotated to rotate the pair of clamp arms 21 and 22 clockwise (S204).

Then, the controller 81 controls the first dog 72
It is determined whether or not the detected surface 72a of the first dog 72 is turned on while facing the reference state sensor 76 (S205), and the detected surface 72a of the first dog 72 faces the reference state sensor 76, and Is turned on, the controller 81 stops driving the rotation drive mechanism 11 (S206). Therefore, the pair of clamp arms 21 and 22 are in the reference state, and the container C is in the upward state.

Further, the engaging piece F1 of the container C engages with the contact portions 26a, 27a of the pair of clamp arms 21, 22.
Next, the controller 81 causes the contact member 65a to be pressed by the engagement of the engagement pieces F1 with the contact portions 26a, 27a, the pivot lever 59a to pivot, and the detected surface 62a to face the load detection sensor 56a. Then, it is determined whether or not the load detection sensor 56a is turned on (S207), and the load detection sensor 56a is turned on.
Is in the off state, the controller 81 determines that there is an abnormality and stops the operation.

When the contact member 65a is pressed by the engagement piece F1, the rotation lever 59a rotates, and the detected portion 62a faces the load detection sensor 56a, and the load detection sensor 56a is turned on. The container C has a pair of clamp arms 21 and
It is determined that the gripping portion 25 is normally supported by the grip portion 25, and the solvent discharging operation is completed.

Next, based on the work data in the memory 83, the controller 81 controls the traveling of the unmanned forklift 1 to the reversing place and stops at the reversing place in order to completely discharge the solvent remaining in the container C. Then, the controller 81 starts the loading operation for placing the container C in the reversing place based on the loading operation data in the memory 83.

As shown in FIGS. 15 to 18, the controller 81 drives the rotary drive mechanism 11 to rotate the gear 8 to completely discharge the solvent remaining in the container C,
The pair of clamp arms 21 and 22 are rotated counterclockwise via the support plate 12 (S300). Then, the detection surface 73a of the second dog 73 of the support plate 12 rotates counterclockwise.

The controller 81 determines whether or not the detected surface 73a of the second dog 73 is turned on in opposition to the reversing state sensor 80 (S301), and the detected surface 73a of the second dog 73 is reversed. When facing the state sensor 80 and the inversion state sensor 80 is turned on, the controller 81 stops the rotation drive mechanism 11. Then, the pair of clamp arms 21 and 22 are stopped in a state of being rotated by about 180 °, that is, in a downward state where the container C is inverted by 180 °. For this reason, the engagement piece F2 of the container C is engaged with the contact portions 26b and 27b, and the container C
It is supported in a loosely fitted state on 1 and 22. Thereafter, the controller 81 validates only the detection signal of the load detection sensor 56b based on the ON operation of the inversion state sensor 80 (S3).
02).

When the container C is turned 180 ° downward, the engagement piece F2 of the container C is engaged with the contact portions 26b and 27b of the grip portion 25. At this time, the controller 81 presses the contact members 65b, 65b, and the rotating lever 59b rotates about the support pin 58b to rotate the detected portion 62.
It is determined whether or not b has turned on in opposition to the load detection sensor 56b (S303). If the load detection sensor 56b does not face the detected portion 62b and the load detection sensor 56b does not turn on, the controller 81 determines that there is an abnormality and stops the operation.

When the detected portion 62b of the rotation lever 59b faces the load detection sensor 56b and is turned on, the controller 81 drives the lift cylinder 6 to cause the lift cylinder 6 to move through the clamp bracket 4, the support bracket 7, and the support plate 12 to form a pair. Is lowered (S304).
Then, the container C is placed on the floor surface, and the engagement piece F2 and the contact portion 2
When the engagement with the engagement members 6b and 27b is released, the pressing of the contact member 65b by the engagement piece F2 is released.

At this time, the controller 81 determines whether or not the load detection sensor 56b has been turned off (S305).
If the load detection sensor 56b does not perform the OFF operation, it is determined that the container C has not been placed on the floor yet, and the lift cylinder 6 is continuously driven. Based on the detection signal from the elevation sensor 82, the controller 81 determines whether or not the pair of clamp arms 21 and 22 have descended by a predetermined amount or more (S306). A predetermined amount or more of a pair of clamp arms 21,
If the load detection sensor 56b has not been turned off even if the load 22 has dropped, the controller 81 determines that the load is abnormal and stops the operation.

If the lowering of the pair of clamp arms 21 and 22 is less than the predetermined amount, the lift cylinder 6 is continuously driven to lower the pair of clamp arms 21 and 22 via the clamp bracket 4.

If the load detection sensor 56b continues to descend while the load detecting sensor 56b remains on even though the engagement piece F2 does not press the contact member 65b, the engagement piece F1 causes the contact member 65a to move. When the load is pressed, the load detection sensor 56a is turned on and the container C may be damaged, so that the load detection sensor 56a is turned on during loading (S3).
07), the controller 81 determines that there is an abnormality and stops the operation.

When the container C is placed on the floor, the engagement piece F2 does not press the contact member 65b, and the load detection sensor 56b
Is turned off, the controller 81 drives the lift cylinder 6 from this point on to drive the pair of clamp arms 21 and
It is determined based on the detection signal of the elevation sensor 82 whether or not the sensor 22 has further decreased by a predetermined amount (S308). When the controller 81 confirms that the pair of clamp arms 21 and 22 have been lowered by a predetermined amount based on the detection signal of the lift sensor 82, the controller 81 stops driving the lift cylinder 6 and releases the pair of clamp arms 21 and 22. The descent is stopped (S309).

In this state, the controller 81 contracts the hydraulic opening / closing cylinder 32 to release the pair of clamp arms 21, 21.
2 is opened (S310). Next, the controller 8
Reference numeral 1 denotes an opening / closing detection sensor 18 based on the opening operation of the pair of clamp arms 21 and 22 by the hydraulic opening / closing cylinder 32.
Is determined to be off (S311), and based on the off operation of the open / close detection sensor 18, the controller 81 stops the contraction of the hydraulic open / close cylinder 32 (S312).

As a result, the container C is placed downward at the reversing place in a state where the container C is reversed by 180 °, and the loading operation is completed.
Then, while the pair of clamp arms 21 and 22 remain open, the controller 81 again unloads the container C already placed at the reversing location based on the operation data in the memory 83, and performs the same operation as described above. Repeat.

As described in detail above, since the container C is detected by the load detecting mechanism 51, even a lightweight container C can be detected reliably, and the loading operation can be performed reliably.

The engagement pieces F1 and F2 of the container C are connected to the contact portions 26a and 26a of the pair of clamp arms 21 and 22.
b, 27a, and 27b, and the container C is transported in an unclamped state in which the container C is supported in a loosely fitted state. Therefore, the container C that is easily deformed and damaged by gripping can be reliably transported. Can be.

Further, when the solvent is discharged by rotating the container C, the solvent adhering to the periphery of the grip portion 25 is removed by the through holes 50a, 50a.
b. And the load detection sensor 5
If 6a and 56b are on the extension of the movement locus of the contact members 65a and 65b, the solvent that has entered through the through holes 50a and 50b may adhere to the load detection sensors 56a and 56b. However, the load detection sensors 56a and 56b
Since it is provided at a position away from the load detection sensors 56a and 56b, it does not adversely affect the load detection sensors 56a and 56b and cause a malfunction. As a result, the transport operation of the container C can be reliably performed.

The controller 81 can control the rotation of the pair of clamp arms 21 and 22 based on the reference state sensor 76 and the inverted state sensor 80, so that the container C can be freely rotated and conveyed. The container C can be loaded in an inverted state.

Further, the controller 81 determines the state of the pair of clamp arms 21 and 22 based on the reference state sensor 76 and the inversion state sensor 80, and activates one of the load detection sensors 56a and 56b in accordance with this state. Become As a result, the invalidated load detection sensors 56a, 56
Since this signal is ignored even if b is turned on, it is possible to carry out reliable transporting, loading and unloading operations.

When the load detection sensors 56a and 56b are on, the controller 81 operates the hydraulic opening / closing cylinder 32 to operate the pair of clamp arms 21 and 22.
Since the opening and closing operation of the container C is not performed, it is possible to reliably prevent the container C from dropping.

The contact portions 27a and 27b of the clamp arm 22 on the side from which the solvent of the container C is discharged are formed to be smaller than the engaging pieces F1 and F2 of the container C, so that the adhesion of the solvent is prevented. can do.

In this embodiment, the clamp arm 2
Although the rotation functions of the first and second rotations are provided, it is not always necessary to provide the rotation function, and it is also possible to simply support the container C with the holding portion 25 in a loosely fitted state and transport the container C. In this case, since the container C is not inverted, the rotation drive mechanism 11, the engagement piece F2, the load detection sensor 56b, the reference state sensor 76 for detecting the rotational position of the clamp arms 21 and 22, and the inversion state sensor 80, intermediate position detection sensor 7
8, the first and second dogs 72 and 73 and the intermediate dog 74 can be omitted.

Although the proximity sensor is used for each sensor in this embodiment, an appropriate sensor such as a photocoupler, a reed switch, and a limit switch can be used instead of the proximity sensor.

In the present embodiment, the solvent is conveyed, but powder such as sand may be conveyed. Further, in this embodiment, the pair of clamp arms 21 and 22 are configured to be opened and closed by the hydraulic opening / closing cylinder 32. However, one clamp arm 21 is fixed and the other clamp arm 22 is rotatable. It is also possible to configure. Further, various work data stored in the memory 83 can be arbitrarily changed as needed.

In this embodiment, the engaging pieces F1 and F2 as the engaging portions are formed on the container C. However, the container C having the body portion curved inward is supported in a loosely inserted state. It can also be transported.

In the present embodiment, the load is embodied in the cylindrical container C. However, the container C (load) does not necessarily have to have a bottomed cylindrical shape. Another bottomed cylindrical shape may be used. In addition, engaging portions F1 and F2
The container (load) does not have to be cylindrical. Furthermore,
The positions of the dogs 72 to 74 may be configured to be movable, and the stop and deceleration detection positions of the rotation drive mechanism 11 and the angle of the intermediate position may be changed.

[0110]

As described above, according to the first invention, there is an excellent effect that a load which is easily deformed or damaged can be reliably transported without being damaged.

According to the second aspect of the present invention, the presence or absence of engagement with the load is directly detected by the engagement detecting means, so that there is an excellent effect that the completion of loading of a light load can be reliably detected. .

According to the third aspect of the present invention, since the detected member of the engagement detecting means for detecting the completion of the loading of the light load is at a position off the movable member, the engagement detecting means malfunctions due to the influence of the load. This has an excellent effect that a reliable transfer operation can be performed by preventing the occurrence of the erroneous transfer.

Further, according to the fourth invention, when transporting the bottomed cylindrical container, the load can be gripped without causing deformation or damage of the load, and the load is reversed. After that, there is an excellent effect that the completion of loading can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a side view of an unmanned forklift according to the present invention.

FIG. 2 is a plan view of the unmanned forklift.

FIG. 3 is a partial plan view showing a clamp device.

FIG. 4 is a partial side view showing a support structure for a pair of clamp arms.

FIG. 5 is a partially cutaway front view showing an arrangement of sensors for performing rotation control of the kunlap device.

FIG. 6 is a partial side sectional view showing a configuration of a sliding shaft for restricting opening and closing operations of a pair of clamp arms.

FIG. 7 is a partially cutaway side view showing a load detection mechanism for detecting a load.

FIG. 8 is a partially cutaway plan view showing a load detection mechanism for detecting a load.

FIG. 9 is a partially cutaway side view showing that the load detection mechanism has been operated by the load locking pieces.

FIG. 10 is an electric block diagram showing an electric configuration of the unmanned forklift.

FIG. 11 is a flowchart for explaining a container unloading operation by an unmanned forklift.

FIG. 12 is a flowchart for explaining a container unloading operation by an unmanned forklift.

FIG. 13 is a flowchart for explaining a container unloading operation by an unmanned forklift.

FIG. 14 is a flowchart for explaining an operation of discharging a solvent from a container by an unmanned forklift.

FIG. 15 is a flowchart for explaining a container loading operation by an unmanned forklift.

FIG. 16 is a flowchart for explaining a container loading operation by an unmanned forklift.

FIG. 17 is a flowchart for explaining a container loading operation by an unmanned forklift.

FIG. 18 is a flowchart for explaining a container loading operation by an unmanned forklift.

[Explanation of symbols]

6 Lift cylinder as lifting / lowering means, 11 Rotational driving mechanism as rotation driving means, 21, 22 Clamp arm, 32 Opening / closing hydraulic cylinder as opening / closing driving means, 5
1a, 51b... Load detecting mechanism as engagement detecting means, 62
a, 62b: Detected portions as detected members, 65a, 6
5b: a contact member as a downward moving member; 76, a reference state sensor as a rotating state detecting means; 80, an inverted state sensor as a rotating state detecting means; 81, a controller as a determining means and an activation controlling means; C: Container as load, F
1, F2 ... engagement piece as an engagement portion

Claims (4)

(57) [Claims] 1. A load, which is disposed at a closed position where it can be engaged with an engaging portion provided on an outer periphery of a load by an opening / closing operation and at an open position where it cannot be engaged, and abuts against a lower surface of the engaging portion to load the load. A clamp device comprising: a pair of clamp arms that support the pair of clamp arms in a loosely fitted state; opening and closing drive means for opening and closing the pair of clamp arms; and lifting means for raising and lowering the pair of clamp arms. 2. The clamp device according to claim 1, wherein at least one of said pair of clamp arms is provided with an engagement detecting means for detecting that the clamp arm has been engaged with an engagement portion of a load. 3. A movable member having a contact portion protruding from a contact surface contacting a lower surface of the engagement portion is provided on one clamp arm so as to be movable between a projecting position and a retracted position. 3. A detection member of an engagement detecting means is provided at a position deviated from the extension of the movement locus of the contact portion.
The clamping device as described. 4. An engaging portion which is disposed at a closed position where it can be engaged with a pair of upper and lower engaging portions provided for a bottomed cylindrical load and an open position where it cannot be engaged. A pair of clamp arms for supporting the load in a loosely fitted state by contacting the pair of clamp arms; opening and closing drive means for opening and closing the pair of clamp arms; lifting means for raising and lowering the pair of clamp arms; Rotating drive means for moving, and a pair of upper and lower engaging portions provided respectively corresponding to upper and lower abutting surfaces of a clamp arm to be engaged with the pair of upper and lower engaging portions. Engagement detection means for detecting, rotation state detection means for detecting the rotation state of the pair of clamp arms, and rotation state of the pair of clamp arms based on a detection signal of the rotation state detection means Determining means, and said determining means Clamping device having a activation controller means for enabling either one of the detection signal engagement detecting means provided in the clamp arm on the basis of.